The changed duration of the time to heading and maturity is an important element of the wheat’s adaptability to specific production conditions. The
question whether a variety early by its heading date remains early by its maturation date is a significant one, but the data on this problem is rather limited.
Therefore the aim of this investigation was to find out if there is any specificity between the varieties by their response to the environment with regard to heading
date and maturation date and if there is any relation between these periods in the common wheat varieties different by their earliness. After preliminary
observations in the trial field of DAI, General Toshevo, ten early and ten late wheat varieties and lines were selected and analyzed. The dates to heading and
physiological maturity were studied. They were identified visually at stage 55 and 94, respectively, by the scale for wheat growth and developments during 2004
– 2009. The genotype, the year conditions and the sum of temperatures (GDD) interacted significantly with the dates of the two traits and therefore affected their
variation. The heading date varied in a similar way in positive or negative direction in both variety groups. The correlations between the dates to heading and
maturity were high and significant regardless of the variety group (r=0.858, r=0.755, respectively). The period between heading and physiological maturity
(grain filling) varied according to the temperatures of the respective year. The date to heading can on the whole be used as a criterion for distinguishing wheat
varieties by their growing period durability. The time from heading to grain maturity was clearly less affected than the time to heading and depended mostly on
the genotype.

Relation between time to heading and date of maturity of winter common wheat varieties (Triticum aestivum L.)

N. Tsenov